This is a small trailer I made for my mountain bike. It was made from recycled materials and some other parts that can be picked up at the hardware store for $10 or less.
Step 1: Main Body
First, get a storage bin with a lid. Then you need ply-wood. Cut the first piece of ply-wood to fit snugly inside the bin. Cut the second piece larger than the bottom of the bin. Next, make a "sandwich" of Ply-wood one, the bin, then the 2nd piece of ply wood centered on the bottom of the bin. Screw it together with screws.